Radio communication system



March 11, 1941. GQSSEL 2,234,244

RADIO COMMUNICATION SYSTEM Filed March 31, 1958 2 Sheets-Sheet 1 March 11, 1941. E G'OSSEL 2,234,244

RADIO COMMUNICATION SYSTEM Filed March 31, 1938 2 Sheets-Sheet 2 J22 V922 for:

Patented Mar. 11, 1941 UNITED STATES PATENT OFFICE I Erich Gessel, Berlin, Germany, assignor to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof,

Germany, a company Application March 31, 1938, Serial N 0. 199,100 In Germany April 8, 1937 4' Claims.

The present invention relates to radio communication systems and more particularly to arrangements for effecting directive wireless transmission and reception.

It is well known to perform telephonic or telegraphic intelligence communication by means of directive radio systems operating at wavelengths of fractions of meters, for example.

The present invention consists in certain features of novelty which will appear from the following description and be pointed out in the appended claims, reference being made to the accompanying drawings, in which:

Fig. 1 is a diagrammatic plan of one embodiment of the invention; Fig. 2 is a diagrammatic sectional elevation drawn in a larger scale than Fig. 1 and illustrating the central station of the arrangement; While Fig. 3 is a diagrammatic sectional plan view of the arrangement shown in Fig. 2 and, Fig. 4 shows a modified arrangement at the central station.

Referring .to Fig. 1, there is shown a central station A being adapted to effect two-way communication with any of the optionally located substations B to G. Each substation has one directive transmitter S and one directive. receiver E. The central station A is equipped with the receivers E'b to E'g individually allotted to the corresponding substation. In order to secure two-way communication, it would be necessary also to provide the central station with one particular transmitter for each substation, a requirement which would involve various disadvantages. For instance, if the central station A is placed on a tower at some distance from ground, it will be obvious that the possibility for providing a larger number of transmitters is extraordinarily restricted due to the space conditions prevailing. Moreover, taking under consideration that a plurality of transmitters in close proximity to each other must be operated at wavelengths which differ from one another by a slight amount only, it is evident that interferences between the transmitters will be inevitable during operation.

The present invention has for its object to avoid these difficulties by the provision of 'a transmitter arrangement in the central station which enables directive communication with each substation with one single directive transmitter only.

According to the invention, thecen-tral station is furnished with one particular directive receiver directed toward each substation allotted to the central station, while having one single transmitter common to all substations. The maximum directive radiating characteristic of the transmitter is automatically adjusted toward the substation, the call signal of which has been received in the central station. This problem is suitably solved by the use of a rotatable directive transmitter which is automatically set into the desired direction in response to the receipt of a call signal.

The principle of this proposition is illustrated in Fig. 1, in which the rotatable directive transmitter Sa is automatically turned into the position which corresponds to the direction toward the substation, e. g. the station C, which is assumed to have transmitted a call signal, so as to enable a two-way intelligence transmission between the two stations.

According to a further feature of the invention, wireless two-way connections may be established with substations of particular importance in the central station A. This figure shows the directive receivers E'g and E'd located in the tower T. The rotatable directive transmitter So. is placed on a turn-table I moved by an electromotor '5 by the aid of the shaft 2 and the bevelled gears 3 and 4. A disc 6, the circumference of which carries a notch, is attached-to the shaft .2. One electromagnet 8g and 8d, respectively, is allotted to each substation, and themmatures of these electrom-agnets are adapted to engage the notch l so-as to arrest the'transmitter in the desired position.

Assuming that the substation G has transmitted acall signal which has been received by the directivereceiver E'g of the-central station A. The call signal thus received renders the relay Rg effective which closes its contact rg so as to operate the slow-to-release relay Vg which closes its contact no. This contact remains closed by virtue of the delayed release of this relay even if the call signal from the substation G decays. The operation of relay Vg completes a circuit from the current source I?) over" the electronic-tor 5, the closed contacts kg and cg through the electromagnet 89 back .to the current source. The motor 5 is then started and The central station A is causes the transmitter Sd to rotate until the armature 9g of the energized eelctromagnet 8g enters the notch, the transmitter thus being arrested in the desired direction toward the calling transmitter. The armature 9g simultaneously opens the contact kg so as to interrupt the energizing circuit for the motor which is then stopped. Meanwhile the siow-to-release relay Vg has restored to normal, so that the contact vg is again open. All switching mean-s operated in the above described cycle are again restored to normal and the transmitter So is arrested in the desired direction, so that intelligence exchange may be entered with the substation in question. In addition, means are necessarily provided in the central station so as to prevent movement of the transmitter Set in response to calling signals from any other substation duringthe com-- municationwith one particular station.

Fig. 3 is a horizontal section through'the central station A. The directive receivers are denoted Eb to Ey. The rotatable directive transmitter Sa has been omitted in this representation for the sake of simplicity. The electromagnets 89 to 8b are provided for each direction of the substations and that electromagnet is at times energized which pertains to the receiving equipment which has been actuated due to a call signal received. In the case under consideration it is assumed that a call signal has been received by the equipment Eb with the result that the electromagnet 8b has been energized and its armature 9b has engaged the notch I of the disc 2 rigidly attached to the arrangement adapted to move the transmitter. The transmitter is thus arrested in the desired position and the contact Icb has been opened. The further circuit elements shown in Fig. 2 have been omitted for the sake of simplicity.

It is obvious that the desired rotation of the directive radiating characteristic of the transmitter may be attained by other known methods. For instance, a particular directive antenna as shown at S'b to. S'g of Fig. 4 may be employed for each direction toward a substation. The call signal from such station being adapted to automatically connect the transmitter So. to the corresponding-antenna by means of a rotatable supply switch. This switch may be controlled by the directly received signals in a manner similar to that disclosed above for positioning the reflector shown in Fig. 1.

What is claimed is:

1. In a two-way directive radio communication system, a central station and a plurality of substations, each substation having one directive transmitter and one directive receiver, the main station comprising a plurality of directive receivers individually directed toward a corresponding substation, a rotary adjustable radio transmitter means common to all stations, directive means for directing radiation from said transmitter means selectively toward any of said substations, rotary adjusting means for said transmitter means, means responsive to a call signal received from one substation for energizing said rotary adjusting means to render said transmitter means and said directive means efiective in a predetermined direction toward said one substation, and means responsive to the rotary adjustment of said transmitter means to said predetermined position for de-energizing said rotary adjusting means and arresting further rotary movement of said transmitter means.

2. In a two-way directive radio communication system, a central station and a plurality of substations, each substation having one directive transmitter and one directive receiver, the central station comprising a plurality of directive receivers individually directed toward a corresponding substation, one directive radiating transmitter common to all substations, a mechanical drive for rotating said directive radiating transmitter continuously in one direction only, a relay arrangement responsive to an incoming call for controlling the rotation of said transmitter, means responsive to operation of said relay arrangement for starting said mechanical drive, and means controlled by said relay arrangement for arresting rotation of said transmitter when the directive radiating'characteristic has reached the predetermined direction toward the calling substation.

3.-In a two-way directive radio communication system, a central station and a plurality of substations, each substation having one directive transmitter and one directive receiver, the main station comprising a plurality of directive receivers individually directed toward a corresponding substation, one rotatable directive transmitting antenna common to all substations, means responsive to a call signal received from one substation for rotating said directive transmitter continuously in one direction only and means responsive'to rotary adjustment of said transmitter to a predetermined position aligned with the calling substation for arresting rotary movement of said transmitter.

4. In a two-way directive radio communication system, a central station and a plurality of substations, each substation having one directive transmitter and one directive receiver, the main station comprising a plurality of directive reoeivers individually directed toward .a corresponding substation, a plurality of directive antenna arrangements individually allotted to each direction toward a substation,-a rotary adjustable transmitter, means responsive to a call signal received from one substation for rotatively adjusting said transmitter for successivev cooperation with said directive antenna arrangement and means responsive to adjustment of said transmitter to a predetermined position cooperating with the directive antenna allotted to said one substation for arresting further rotary movement of said transmitter.

ERICI-I Gossiin 

